Saddle clamp

I'm after a bit of advice. I recently bought a selle itallia saddle with carbon rails for my new bike, to replace the horrid mess of a saddle the new bike came with. Except it don't fit my seat pin. the carbon rails are too thick for the clamp and a little too close together to fit in the top of the pin. I take it this means I need a new seat pin, can someone point me in the right direction for a reasonably priced selection? I'm a little out of my depth with this one.
Thanks.

I had fat seat rails and my easton ec70 seatpost took it fine,maybe worth taking your saddle into the velocity shop in portsmouth or somewhere like the fishbourne cycle shop which im sure could you find you what you need
,i dont think you can buy just the top pin that holds it in though,i dont know

pointing in right direction? This may be a start.....

http://answers.wiggle.co.uk/answers/7867-en_gb/product/5360043169/carbon-1bolt-seat-post-clamp-for-carbon-rails-questions-answers/questions.htm?expandquestion=151573

....it depends if your seatpost will accept the bolt? All the best